High Concordance and Negative Prognostic Impact of RAS/BRAF/PIK3CA Mutations in Multiple Resected Colorectal Liver Metastases

Clin Colorectal Cancer. 2020 Mar;19(1):e26-e47. doi: 10.1016/j.clcc.2019.09.003. Epub 2019 Dec 12.

Abstract

Background: The prevalence and clinical implications of genetic heterogeneity in patients with multiple colorectal liver metastases remain largely unknown. In a prospective series of patients undergoing resection of colorectal liver metastases, the aim was to investigate the inter-metastatic and primary-to-metastatic heterogeneity of mutations in KRAS, NRAS, BRAF, and PIK3CA and their prognostic impact.

Patients and methods: We analyzed the mutation status among 372 liver metastases and 78 primary tumors from 106 patients by methods used in clinical routine testing, by Sanger sequencing, by next-generation sequencing (NGS), and/or by droplet digital polymerase chain reaction. The 3-year cancer-specific survival (CSS) was analyzed using the Kaplan-Meier method.

Results: Although Sanger sequencing indicated inter-metastatic mutation heterogeneity in 14 of 97 patients (14%), almost all cases were refuted by high-sensitive NGS. Also, heterogeneity among metastatic deposits was concluded only for PIK3CA in 2 patients. Similarly, primary-to-metastatic heterogeneity was indicated in 8 of 78 patients (10%) using Sanger sequencing but for only 2 patients after NGS, showing the emergence of 1 KRAS and 1 PIK3CA mutation in the metastatic lesions. KRAS mutations were present in 53 of 106 patients (50%) and were associated with poorer 3-year CSS after liver resection (37% vs. 61% for KRAS wild-type; P = .004). Poor prognostic associations were found also for the combination of KRAS/NRAS/BRAF mutations compared with triple wild-type (P = .002).

Conclusion: Intra-patient mutation heterogeneity was virtually undetected, both between the primary tumor and the liver metastases and among the metastatic deposits. KRAS mutations separately, and KRAS/NRAS/BRAF mutations combined, were associated with poor patient survival after partial liver resection.

Keywords: Colorectal cancer biomarkers; Method sensitivity; Mutational status; Sequencing; Tumor heterogeneity.

Publication types

  • Observational Study

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Biomarkers, Tumor / genetics*
  • Class I Phosphatidylinositol 3-Kinases / genetics
  • Colorectal Neoplasms / genetics
  • Colorectal Neoplasms / mortality
  • Colorectal Neoplasms / pathology*
  • Colorectal Neoplasms / surgery
  • DNA Mutational Analysis
  • Disease-Free Survival
  • Female
  • Genetic Heterogeneity
  • Hepatectomy*
  • High-Throughput Nucleotide Sequencing
  • Humans
  • Kaplan-Meier Estimate
  • Liver / pathology
  • Liver / surgery
  • Liver Neoplasms / genetics*
  • Liver Neoplasms / mortality
  • Liver Neoplasms / surgery
  • Male
  • Middle Aged
  • Mutation
  • Neoplasm Recurrence, Local / epidemiology*
  • Neoplasm Recurrence, Local / genetics
  • Norway / epidemiology
  • Prognosis
  • Prospective Studies
  • Proto-Oncogene Proteins B-raf / genetics
  • Proto-Oncogene Proteins p21(ras) / genetics
  • Young Adult

Substances

  • Biomarkers, Tumor
  • KRAS protein, human
  • Class I Phosphatidylinositol 3-Kinases
  • PIK3CA protein, human
  • BRAF protein, human
  • Proto-Oncogene Proteins B-raf
  • Proto-Oncogene Proteins p21(ras)